The lance tubes of long retracting sootblowers which during operation are projected into high temperature zones of heat exchangers such as large public utility and industrial boilers and the like are protected against heat damage while in the heat exchanger by the cooling effect of the blowing medium (typically steam or air) flowing therethrough. (References herein to "boilers" are intended to encompass other types of heat exchangers). In order to enhance the efficiency of such cooling effect, turbulizing devices are commonly used at the open end of the feed tube to impart a helical motion to the blowing medium as it enters the lance tube, thereby providing a desired degree of turbulence and increasing effective contact between the blowing medium and the wall of the lance tube.
Where high rates of flow of blowing medium are required, the use of turbulizers has in the past become impractical, above certain flow rates, because vibration of the feed tube occurs and under some conditions is so severe that the resultant impacting of the feed tube against the lance tube causes rapid failure of the latter due to fatigue.
The overall objective of the present invention is to provide an improved turbulizer-equipped sootblower feed tube and lance tube construction which prevents such damaging vibration and failure at flow rates up to values greatly exceeding those which could previously be employed.
Other objects and advantages of the invention will be apparent to persons skilled in the art upon consideration of the present disclosure in its entirety.